Uncurling device for sewing machines



Jan 24, 1961 J. M. WASHBURN UNCURLING DEVICE FOR SEWING MACHINES 5 Sheets-Sheet 1 Filed Oct. v, 1955 Inventor: c/bhnM Was-lab urn His/1 torneysJan. 24, W61 ,J. M. WASHBURN 2,969fi28 UNCURLING DEVICE FOR SEWINGMACHINES Filed Oct. 27, 1955 5 Sheets-Sheet 2 Inventor:cfohnMTVashlaurn/ By M W Jama 24, 196E Filed 001;. 2'7, 1955 5Sheets-Sheet 3 [nven tor: Jbhn M Washburn .299 M am Patented Jan. 24,1961 UNCURLING DEVICE FOR SEWING MACHINES John M. Washhurn, WestHartford, Conn., assignor to The Merrow Machine Company, Hartford, Conn,a corporation of Connecticut Filed on. 27, 1955, Self. No. 543,113 8Claims. (Cl. 112-18) This invention relates to sewing machine feedmechafabrics having a tendency to curl along their edges.

Before marginal or overedge stitching is applied to such fabrics, thecurl adjacent the fabric edge must be fiattened and needle, that is,formed and anchored in the work. A primary object of the presentinvention is to provide in a sewing machine a device for uncurling andholding a margin of the work material in flattened and unstretchedcondition as it is fed to and receives the needle.

Another object is to provide a device for uncurling and other feeddevices to produce varying degrees of differential feed of material. Inthe achievement of action to the work if the fabric such actiondesirable. Another feature of the invention resides in mechanism formanipuwill become apparent from the following detailed descriptron takenin conjunction with the accompanying drawings.

Fig. 2 is a fragmentary plan view partly in section of the mechanismshown in Fig. 1;

Fig. 3 is an elevation view of the mechanism shown in Fig. 1 as seenfrom the right;

Fig. 4 is a view similar to Fig. 2 showing a modified form of uncurlingblades and needle plate;

Fig. 5 is a fragmentary plan view showing work with stitches appliedthereto and with some of the stitches supported by a stitch fingercomprising a part of an uncurling device;

Fig. 6 is a view similar to Fig. 1 but showing additional parts wherebyuncurling blades operate to alternately grip and release the work; and

Fig. 7 is an elevation view partly in section of the mechanism shown inFig. 6 as seen from the right.

Referring first to Figure 1, the machine frame 1 supports a main driveshaft 2 operable to actuate various movable parts of the sewing machineincluding a needle carrier 3 and a feed dog carrier 4. A curved needle 5may cooperate with either an upper looper 6 or with both such a looper 6and a lower looper 7 to form overedge stitches respectively of two orthree threads. A needle or throat plate 8 is slotted to accommodate afeed dog 9 supported by feed dog carrier 4 and operate substantially inrear of needle 5. Opposed to feed dog 9and needle plate 8 is the usualpresserfoot 10.

For actuating feed dog carrier 4 to move feed dog 9 in four-motionfeeding movements, conventional mechanism is employed which includes alink such as 12. A similar link 13 is driven by an eccentric 14 on shaft2 and is pivotally connected at its opposite end to a carrier 2'15 bymeans of stud 16. Carrier 15 is slidably supported for oscillatingreciprocatory movement upon guide rods 18 and 19 which are fixedlymounted upon a bracket 20 secured to machine frame 1 by screws 21 and22. A standard 23 is extended upwardly from carrier 15 to support thefabric uncurling and holding device indicated generally at 24.

Uncurling device 24 includes a separator blade 25 formed at the distalend of an arm 26 extending from standard 23. Each of a pair of uncurlingelements indicated generally at 28 includes a yoke 29 having anuncurling blade 30. Yoke 29 includes opposite branches .31 and 32 whichare employed to pivotally mount yoke 29 upon respective pins 33 and 34projecting from standard 23, thereby allowing uncurling blades 30 to bepivoted toward and away from the intermediate separator blade 25.

Separator blade 25 and uncurling blades 30 extend along the path inwhich material is fed to the stitch forming mechanism. Material beingfed is gripped between uncurling blades 3@ and separator blade 25 (seeFig. .5) along the marginal edge of the material. The oscillatingreciprocatoly motion imparted to carrier 35 and blades 25 and 3t) enablethe blade to uncurl and fiatten the material as it is moved toward theneedle while the gripping force exerted between uncurling blades 30 andseparator blade 25 permits slippage or relative movement between thework material and the gripping blades upon movement of the blades awayfrom the needle. Since different thicknesses of material, or types offabric, may require greater or lesser gripping force, adjustment of thegripping force exerted by the movable uncurling blades 30 is obtained bypositioning nuts 35 upon a threaded rod 36 fixedly mounted in lug 37which projects from standard 23 to vary the force exerted by compressionsprings 38 which are sleeved upon threaded rod 36 between lug "37 andthe respective uncurling elements 28. Jam nuts 35 are also mounted uponthreaded rod 36 to maintain nuts 35 in their adjusted position. Bysuitable location of nuts 35, the gripping force exerted upon materialbetween blades 30 and separator blade 25 may be regulated to an amountwhich is sufficient to uncurl and flatten the work material during theright to left stroke of carrier 15 while at the same time permittingslippage between the blades 30 and 25 and the work material when thecarrier is driven in the opposite direction by link 13. In order thatthe spacingbetween separator blade 25 and blades .30 may be temporarilyenlarged to introduce work material between the blades, finger grasps 40are extended fromthe forward end of uncurling elements 28.

As shown in Figs. 1, 2 and 5 each of uncurling blades 30 is providedwith a stitch finger 41 extending rearwardly at one side of needle 5.Work is fed directly from uncurling device 24 to finger 41 whichreceives and initially supports enclosing stitching 42 (see Fig. 5).

A modified arrangement for supporting stitches during their formation isshown in Fig. 4 and includes a stitch of the work material to whichstitching is to be applied.

The amount of travel of either carrier 4 or is determined by the amountof eccentricity of the eccentrics employed to actuate the respectivelinks 12 and 13. When the eccentrics are alike feed dog 9 and uncurlingdevice 24 move respective distances that are equal. When the eccentricsare different the respective feeding elements move a different amountand effect a difierential feeding action.

In the feed mechanism shown in Figs. 1, 2 and 3, uncurling device 24engages the work throughout the cycle of reciprocation. During thefeeding stroke there is little or no relative movement between theuncurling device and the work but during the retractive stroke, whenfabric uncurling is accomplished, slippage is required between theuncurling device and the work. This action is satisfactory with fabricsof certain character but if the work fabric is, for example, of a highlyelastic nature it is desirable that the uncurling elements grip the workonly during the feeding portion of the cycle and release it duringretractive movement.

Structure for accomplishing the desired gripping and releasing action ofthe uncurling elements is shown in Figs. 6 and 7. In this embodiment,each uncurling blade 30 has formed thereon a lug 50 which extends into apath followed by a cam 51. Cam 51 is located at the distal end of an arm52 which is secured to link 13 by screw 53.

Counter clock-wise rotation of eccentric 14 as shown by arrow X in Fig.6 moves link 13 and carrier 15 to the right as shown by arrow Z andimparts a retractive movement relative to needle 5 to uncurling device24. At the same time rotary oscillation of link 13 about pin 16 swingscam 51 slightly in a counter clock-wise direction as shown by arrow Yand forces lugs 50 apart, thus causing uncurling blades 30 to swing awayfrom separator blade and release their grip on the work material. Whenlink 13 moves to the left, cam 51 moves in a direction away from lugsand uncurling blades 30 move to resume their gripping hold on the workby action of springs 38.

It is distinctly to be understood that the invention is not limited tothe exact details of construction hereinbefore described and illustratedin the accompanying drawings as these details may be modified withoutdeparture from the scope of the invention as defined by the followingclaims.

Having thus described the invention what I claim is:

1. In a sewing machine having a frame, a stitch forming mechanism, afeed dog mechanism for feeding material to said stitch formingmechanism, and means for driving the aforementioned mechanisms insynchronized movement; a fabric uncurling and holding device comprisinga carrier mounted upon said frame for movement toward and away from saidstitch forming mechanism along the path in which material is fed to saidstitch forming mechanism, means connecting said carrier and 'saiddriving means for driving said carrier in cyclic oscillating movementsynchronized with movement of said feed dog mechanism, means upon saidcarrier including opposed blades extending along the path of feed forengaging and flattening the marginal edge of work material presented tosaid stitch forming mechanism, means resiliently biasing said bladestoward each other to grip the marginal edge of work materialtherebetween, and

means on said connecting means for moving said blades toward and awayfrom each other to respectively grip and release work material insynchronism with the cyclic movement of said carrier.

2. In a sewing machine having a frame, a stitch forming mechanism, afeed dog mechanism for feeding material to said stitch formingmechanism, and means for driving the aforementioned mechanisms insynchronized movement; a fabric uncurling and holding device comprisinga carrier mounted upon said frame for movement toward and away from saidstitch forming mechanism along the path in which material is fed to saidstitch forming mechanism, means connecting said carrier and said drivingmeans for driving said carrier in cyclic oscillating movementsynchronized with movement of said feed dog mechanism, opposed bladesmounted on said carrier and extending along the path of feed forflattening the marginal edge of work material presented in said stitchforming mechanism, means biasing said blades toward each other to exerta pressing force upon said work material, and means for adjusting saidpressing force to permit relative movement between said blades and saidwork material during movement of said carrier away from said stitchforming mechanism.

3. In a sewing machine having a frame, a stitch forming mechanism, afeed dog mechanism for feeding material to said stitch formingmechanism, and means for driving the aforementioned mechanisms insynchronized movement; a fabric uncurling and holding device comprisinga carrier mounted upon said frame for movement toward and away from saidstitch forming mechanism along the path in which material is fed to saidstitch forming mechanism, means connecting said carrier and said drivingmeans for driving said carrier in cyclic oscillating movementsynchronized with movement of said feed dog mechanism, opposed bladesmounted on said carrier and extending along the path of feed forflattening the marginal edge of work material presented to said stitchforming mechanism, means biasing said blades toward each other to exerta gripping force upon said work material, and means for retracting saidblades to release the grip of said blades upon said material duringmovement of said carrier away from said stitch forming mechanism.

4. In a sewing machine having a frame, a needle plate mounted on saidframe. a stitch forming mechanism operable adjacent the forward end ofsaid plate, a feed dog mechanism located rearwardly of said stitchforming mechanism and operable to feed work material thereto, and meansfor driving said mechanisms in synchronized movement; a fabric uncurlingand holding device comprising a carrier slidably mounted upon said framein front of the forward end of said plate, means connecting said carrierto said driving means for driving said carrier in reciprocatory movementtoward and away from the forward end of said plate along the path inwhich material is fed to said stitch forming mechanism, opposed bladesmounted upon said carrier and extending along said path in whichmaterial is fed, resilient means urging said blades toward each other togrip work material therebetween, and means for regulating the grippingforce exerted by said blades upon said material whereby relativemovement may occur between said blades and said material during movementof said carrier in a direction away from said stitch forming mechanism.

5. In a sewing machine as recited in claim 4, wherein the ends of saidblades remote from said needle plate are shaped to uncurl the marginaledges of work material entering the space between said blades when saidblades are moved relative to said work material.

6. In a sewing machine having a frame, a stitch form ing mechanism, afeed dog mechanism for feeding work material to said stitch formingmechanism, and means for driving the aforementioned mechanisms insynchronized movement; a carrier movably supported upon said frame formovement toward and away from said stich forming mechanism along thepath upon which material is fed to said stitch forming mechanism,opposed uncurling blades mounted upon said carrier for movement towardand away from each other, means including an eccentrically driven linkfor oscillating said carrier along said path in synchronism withmovement of said feed dog mechanism, and means mounted upon said linkfor moving said uncurling blades toward and away from each other.

7. In a sewing machine having a frame, a stitch forming mechanism, afeed dog mechanism for feeding material to said stitch formingmechanism, and means for driving the aforementioned mechanisms insynchronized movement; a carrier mounted upon said frame for reciprocatory movement toward and away from said stitch forming mechanismalong the path upon which material is fed to said stitch formingmechanism, opposed uncurling blades mounted upon said carrier formovement toward and away from each other, resilient means biasing saiduncurling blades toward each other, a link pivotally coupled at one endto said carrier, eccentric means rotatable by said driving means coupledto the other end of said link, an arm fixedly mounted upon said link,and means on said arm movable between said blades during one portion ofa cycle of movement of said link to move said blades away from eachother and movable to a position clear of said blades during theremaining portion of said cycle to permit said blades to move towardeach other to grip work material therebetween.

8. In a sewing machine, stitch forming implements including a needle,fabric feeding means substantially in the rear of said needle, fabricuncurling blades in front of said needle extending along the path inwhich fabric is fed to said needle, means for driving said feeding meansand said needle in synchronized movement, means coupling said fabricuncurling blades to said drive means to impart advance and retractivestrokes of said blades along said path in synchronism with the movementof said feeding means and said needle, and means on said coupling meansfor moving said blades toward each other to grip fabric therebetweenduring the advance stroke of said blades and for moving said blades awayfrom each other to release the fabric during the retractive stroke ofsaid blades.

References Cited in the file of this patent UNITED STATES PATENTS645,539 Allen Mar. 20, 1900 730,945 Merrow June 16, 1903 1,288,735 StiegDec. 24, 1918 1,546,202 Chenoweth July 14, 1925 2,208,992 Lewis July 23,1940 2,339,574 Kurcera et al. Jan. 18, 1944 2,669,203 Hiltbrunner et a1Feb. 16, 1949 FOREIGN PATENTS 345,070 Great Britain Mar. 19, 1931142,416 Sweden July 23, 1953

